This invention relates to battery testers that are incorporated in, or on battery cell labels or packaging.
Know types of batter testers that are placed on batteries are so called "thermochromic" types. In a thermochromic battery tester, a thermochromic display is placed as a narrow, elongated region of a label. The display is typically a single narrow and elongated region. The thermochromic battery tester operates by a consumer depressing a manual switch. Once the switch is depressed the consumer connects an anode of the battery to a cathode of the battery and can read the relative power remaining in the battery. The connection goes through a silver conductor that has a variable width so that the resistance of the conductor also varies along its length. As current travels through the silver conductor, the current generates heat that changes the color of a thermochromic ink in the thermochromic display over the silver conductor. The thermochromic display is arranged as a gauge to indicate the relative capacity of the battery. The higher the current the more heat is generated and the more the gauge will change to indicate that the battery is good.
In order to test the battery the display needs to be aligned so that the consumer can read it. Also, sometimes the switch can be hard for people to depress and it becomes difficult to tell whether the tester worked or not or whether the battery is good or bad. This can be confusing to a consumer. Depressing the switch makes a direct relatively high conductance connection between the anode and cathode of the cell which can draw significant power and reduce battery lifetime.